SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26d0f68657f25ac21aa57daba3648f2b63631951da15bb9e62e017bfe313b976' 
  AND token = 'Cv6gKst3PVzKYohUqJP4tt42XhGso9In8JAjzJggj+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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