SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '659ffd75bf253d479dc8760458b98dcf11258448d472eac367793eea0ad25422' 
  AND token = 'pruMFIwh/lN7i0/Q9pJUT3rKW3TQdKULsMtM5ThUJ38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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