SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '253c174fbdcb16b01b5d1db87c71792699f5e8a809f25e9e4bebb5a8652a3b64' 
  AND token = '7w/HG9eKfhg45MrgGK+BpOwZB0fP4YXfTnii2TC7I2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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