SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a4bc03565ead463ee1046cc77be0896aed1d4c9328cebd2245d157a34234ee3' 
  AND token = 'Fc8FMGQg43rUJqRK4pUv2IPodmSmYXx9AtTAWaAiDsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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