SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ca8d79f9c17cbe7458caa66d92241defeb6abdcc10d8d5ca6401ce51bc3cba' 
  AND token = 'M93rWH2d3pH3+jW9QldFYGKBhi801VnQXulJhyV+K1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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