SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c5283c6446467d5372a9f7eb79bf4ad7aca4d740865a1dddcf985ce597f6ec2' 
  AND token = 'XQET9R1ohe0isllqOlaYW/Ls232MDZfQNdHE5xa3MvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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