SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e4ff998e62950814c9a812ea84a83d0a03ab2b09d033fe2b1ad60011cdd0e4cb' 
  AND token = 'mu/96lakM++JgPQW5aQdGsIyZzKX0jmAF5YkIs9d0zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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