SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f5e7df16a2c70859acd4470c493e357391a6649680143ac3f083bdff550cfe0' 
  AND token = '6fSVw40JGsgZ+OVgps+LcBfjPBUlNH1dCQYSh2+CH6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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