SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a58e6b4e6b99f4054944b2b7e90d49330fcdf943d402aa951c1737c03b299dbc' 
  AND token = '/GLwQpptg+0gBIztUVMVC7Lh4DiCmBv12U8oDU+41z8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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