SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92a20f80099bd3ea8591647fc9d0f051a1cfba0b83f598b967f8626f1487c565' 
  AND token = 'sb8LDZgOcWYPIQwztfqjRsgdMYTEL3S3cQkEzQ/lnl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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