SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3c22c7f192fe30cc29f11941f6df74f495a9e6519962567bc87b245c71a25d3' 
  AND token = 'vWvGhaMch6QmdcRP4MGOG2N4BFtQz2K7akPptuls8AE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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