SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81e1fa09c77bd0b41562852f3d9d605bd1dd15cde426fffa8f58cfd20e6ba79c' 
  AND token = 'Zl3lXCoB/zL+KOLdzJC+VVRIXPHq6mTrihlb8HPfWOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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