SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f9bcd640f38f02ca99407954dee743e4dec753294ee1f9a0c3193c148764435' 
  AND token = 'pfBKpZbaJp1cXzPOISMTAMuHnwhQCOJOT8ZOSdBaqWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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