SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5143d684d8f3a56ca799909426dd5552369ae079e2d6875e2092852f9597ca0f' 
  AND token = '/i07n6s7EUrWLnsJM5v4m8vucf/O36RwNjmlDLTsHLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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