SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34fe8227ebda52525dcead7963e4065a2848723484012c0ad3d5e689333a267e' 
  AND token = 'ELtPVzsvGzL1ORYsa6pxu6PoBs38w/jWPhKoWhPVWLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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