SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46694841ec2863da64e11b1a4d16b7441a702122d2c28ba1899b33b8d5c582f6' 
  AND token = 'mnlyvPCI29dYNC7RNHAZZ0kw+b70dsLhm/xCOQDAgoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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