SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5ac06fc24890c87cfb1b2fb572d1bcd9026739bb14a34b9ea07190757742235' 
  AND token = '6fVh/FGgKV+MB4jLNQvZJqT2ORl21q7EOIMkZdLZXmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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