SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5e9cf598792c5657240d8f66fa49856904cafe7775902ce431b9bb09d6b6c7a' 
  AND token = 'ACr+3Fpgn1sZjS5n5e2vi+pR3/CjomAG52XEWmmkPBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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