SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9befa89f2ac9dafe60e0f2d9a16531d86426d210813b618990ca35df059fd17' 
  AND token = 'PoFRCz/w7A/NB+ONd2LVCdZJdfxDxhPcKyYovtQANDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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