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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a45ad9b904152badb4fcf09419f2dfe1e2c5a3f968828793d2ae421d05e2b5c9' 
  AND token = 'YwRF7ud+e/DcRZ7v/FMmzivEi5B7fEJEFpaCUOdQMYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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