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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c21d49d9a5a2e7a47ac427c3b7c7d6cd0539a4a0eb329be274b320c9af055ad5' 
  AND token = 'Z4l8+AiMswvtEEWNQW8O+xGU9kj4dbu89Jn/zKvftAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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