SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08554a20c8982078129f491a9bbf5f950f4531bee03fae02463e1c094431147b' 
  AND token = '/XSfkrgyubFE+PthH+6E6ayW6N+ozhUzpLnoR3PwfBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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