SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd57cdc5d9c6b7c2354972cd0779b60206b1068c83ecc8ff33a9bf07d28b3b3f' 
  AND token = 'iQlpqDdUk+x0LRqDN1qaOxYw7GelDoixeF2vJwgn+aA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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