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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ec95c334531b196ca9a9b181bf5e6a4714016c0259b50910942bd5c5078cd5d5' 
  AND token = 'PG2S4Za5uC6lfzkWn1ju/hY8Gvu6d4hsRZqcY0rDXSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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