SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a79d8920430a7c1574201208462a5c5ad394895505178f2a8cc4ddf3e8383d83' 
  AND token = 'oytZQsKyGzhRwKoOKSWfB77YWdLTXkUSdubAD1/c8aY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}