SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54a5f1e88f73b4a29943fb80197454932289ef853157ba12b852060741d800ca' 
  AND token = '9yKfdNqKXbSARAUSJcoNFCTlC1YetIyaeengxjuxsc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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