SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b5f46a2403dcd905b22aba96b883ccd35d2c3468920b9bbed596844584ae1cd' 
  AND token = 'ooNiJlJdxouj0cv5LHC1+3IQKMto7YhgCYeNzZW+iNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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