SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0811fffc4fc7a797c71b09b0d206e1966cd2412fa6ab35eae183c41ac61a524b' 
  AND token = 'B5OBZ8o3FhZVXWRQgqhCRAfJVANT+5tDYuAO6EQMFj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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