SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a84518d3155468e697305e51b9b402a8c72afba3a161a7e32beaa4ffacd6a75' 
  AND token = 'Zlgc5kXXHgoYgeqZm5sjG28V2F3J5EjYu3ysjMOUYN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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