SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5366f497f2dd60f7bc73a794c765748100dba3b9eef811e9a1d6a0afe6a735e' 
  AND token = 'hxJ/iU3G4UpytvyDj+2JNVdjmLDc6yeGHKJ02AAq7fs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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