SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a75eb5724b10a9910b5d63cfd667130e565be9ebb305764b88f70d0f64d384cf' 
  AND token = 'HcvGnqITq82jdKCiScNeClI8l6mlzcLpZD+CExV7e5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}