SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ba90947926cd70bc496b222e72fb22322bcca2b9b9946dbd6588a2f7e78894d' 
  AND token = 'Q5ZiXKjEM+o6txbik2wxn/d9aJK9mKRDQghcEiwRacQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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