SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca47e2f56a4130a487b594fce326d2d01e71ed022fada838d8049b15c6d538b9' 
  AND token = 'VHb6f+mQ9uJ+iwFHIHrzbYY8gbJSMAxQ27xg461zOhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}