SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bc81a8b47a1f52d1d9440fce35c2ca8ff93e924a02c56b1f7e0c0cdf20e6e241' 
  AND token = 'LVUZNxhJ5VlvBYmP9rkNEmDgfKSMP9U3R9YmjyIjimQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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