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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2670173ae579bdb252280ea1dd424658360b1c51b06802df2a14ad7b412faa7f' 
  AND token = '43+BANvWCCa9wQNt98sjU6aF+BPKrfn+up3fCyD8kiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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