SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5085eda24aadb3e425562b44cb67d2639cd8e84c140420832ed4bd054c992d62' 
  AND token = '5RZB9YxeX7l7x7PQOFDvBAohezFWXQWvll/gKC8CazQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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