SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '338488a39281c0e16658f3e230f4a03b50a76cd471bcf93b337e22abd63e85cf' 
  AND token = 'HOnpdBe+tFzEcnhCF+4sllVeq5RooN+J1tfZI8/G9Ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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