SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd786784ec610887ff23697763396b3c8150ab44f070ef15cf9f8c1cb9785cab6' 
  AND token = 'ktAk5Kqup7lU5oLJlCDAnFDh/r8Yd3mLhs67hpEkXv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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