SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b21c91df320dfdf59f98b11748bc346c21617dca7f70d0b0fecde6e5d8843d15' 
  AND token = 'lwU54GSy08QaTuE62yEKWSb1l1ZveD4k+kaxL9FFoh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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