SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3ffd66530620df10105876f19622f8af8f006f73d5552a2723aee4287a1f32c' 
  AND token = 'CXW8nTVduqCuZ5mqUzng7sH52nrpk+xdr1wWG8Q3Lr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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