SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a771024e8f1c73c343bf5b8ce5f4f91965df277fc7a19925d937fd71789454da' 
  AND token = '+b+o38GAlR1Z3uhU9VJRRuahjg9PgbyK+P1QoBJlAoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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