SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9e199f11ac3cb282097df3991c7e67ee444af3410db4ef19c23d8ec2b20c550' 
  AND token = 'eifQpOTWru7IN/jEp7zdrLiNdHwfwRJBv8GPXgCiXr4=' 
  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"
    }
  }
}