SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b85777dc32b26d3fa59039d86e8f056be9afbfa31f38147dce31065693192a41' 
  AND token = 'gVhnEv8OJE42FYAdoMoJxpCRirR4iTlEcwAjnoHqhOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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