SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37c437907c2c6f0162dd7220eef7f7944eae620f50adbff78c86132925a133b6' 
  AND token = 'wbPhKHbqeSktQxTADBKJ0rrXhcfuqipzE2IwzYOveEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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