SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe934bb3d32d4630d5446de1bfc2d7f4890178799a5536fc9d1ba1475e75b2c' 
  AND token = 'v6B+8LZEm7qGmg+6Y7SXXkgDNh60yxwhClI3epbivXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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