SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9fdb81d80b76fc7a240a3e2b347b3df0b24695a5c5b7157fe1cd0c786f3172f' 
  AND token = 'Yw4nrUDdQC4vpul3IB3gZeEKGNKD4AR+jxrovbG2mG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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