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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6535342e2caacd03dcfa5a0f7be20e65d39ec0aeeead5bf2e5e88de3d3cd093b' 
  AND token = '5AFeGhPcBeXcZzBgjZKJjYrpdbeHaujUOevT5gh5Xog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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