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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bc5f256b03a7b844d9b4ee6157ca604888809a5a2f5d9b66b0a60d3b47ced4f9' 
  AND token = 'xMRqKOjacVYQ+snxFxZoR0psun3cVRPffLzA3LO1Poc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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