SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91a854ff7dfb5ac27b445ac51b2bd4fbb460cc04691373ccfd65f20a2005a59b' 
  AND token = '2uXBn1tdOmxHAMSYgU+jQ/aF1J9OVj5ejGDCUqhpWCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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