SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df3dd24f63857562e093aad02d8f53d6c65515b2fdd72f56b5edadd899c77d7e' 
  AND token = 'zOuTMzzVDtRHPPjjB1EICUUzIT0Krlix0ctI9ezxGag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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