SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62c6f1d34e4c6a0a3f6b900c3abe857a5f1e08cc03a5cfe8963d7bf8bab29fa5' 
  AND token = 'oqLBrLLZmplpINHzy0yh+dCvQE8zR8ZYZPvYOuh+0Mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}