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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '08c392f8d84499efb17434d57ce3f6b12c1f9cbec3517e6ef5fb17d91af9bb3d' 
  AND token = 'tIoOYalFs1WHOtXWFh+egsAHC7rgAGRTuMmYpRWjOag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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