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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3b9fd0d330bcd98ed9e4df84d7b4be85ccd7941890be4071e0263bb1a4def27c' 
  AND token = 'ZZQBnTwW3+7XEd0oHA4x/O/tUCwVI9J3nAxe1sA3JLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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