SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd77da1688f460742eaabc2205c5b2ec88f91b7ba7a0eaad6b9945777120bfb45' 
  AND token = 'KYCgVa1QIYBjLtX30CWfd4LbDvYP8YzKOTosNyyuquE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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