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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f81a28cf94fbfe6ad9c1cf967eb9be59fbeb89b98a45a71b48348d2030f249bf' 
  AND token = 'uaQmSL2za0ExzjcLtBbf/yFY1LxkAfEIpz9i6J0Ui7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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