SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '902f5d4e6a8687e3c34e791515269310056bf5ee91b93c3027fdfffe227785a3' 
  AND token = 'L8t3Ykcun0znyd37Cabtvx9inG+HgneWo7yIFdIF0EA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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