SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acfd6fdb95815a26f3e83ef2df86fca140a823e21b708e95f7535525be13f9bd' 
  AND token = '+hkAO3XJN9531U4qSyxgSab/g9q33BTjj+KsJPKnUVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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