SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5071a0cb291ac3c1f749f0d1071f9afb014aeb3342332f215fa9bcd127b76fa2' 
  AND token = 'rHM4GR0DUT4sqAj8wj1383eaw1fqz75+qzfHpkY92Lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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