SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f025902ca7485b7359dc38b157132059706a21f1d3d376c98c4214b13539ce4' 
  AND token = 'jjjQVUBeyWp+ruGh2yG2tc0UQ8xGRz2ZmoFgLXLnD20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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