SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dcf37318367e4c14a1bc73069be93608641c4f031572a491adad91eeb8b77e0' 
  AND token = 'JQHDHhSxZiYXEZ03VWBiVnkOJ4sf71njKIuBUCvA9qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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