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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9754510e3b6fdf1782fc491165faf6e358c8719a5a4233f9d8011fcf8576a403' 
  AND token = 'DjIAHG3c3v6GroG99CMIsAm8nDz0AJ88iG/yyErxVA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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