SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1bb42032216cf402417205bfc78d78475b0e354f246d372f2f26d21788f4290' 
  AND token = '2H8sBAq9V+MUgkG33H9rCbBCW4JuHwjwbuF6JdqZoyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00133

JSON explain

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