SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b75d16d3d53aacb3f4ee49cc864a44541854526e2e054ca24eb4e90d808e2723' 
  AND token = '/5eEMEQbCbuvPYc4/hrBUTcNRfWz6yqzcG+PIf7v1zA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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