SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ad045117b32a97c4519c3e3473cd94732d17540a270028bbc710e480bc7c062' 
  AND token = 'X+yCdEIaF/OMww65mKOjLgFEEEmSZtHa0T1Qj0yk7PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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