SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a015bf678e59d6be53fb15a6f4c5de12693931b16a0e6ed3725f118b88c1e20' 
  AND token = 'cCBw5LyixuJgJiVFFTYKP4fB8iJN5G2OjIkvPzHB9Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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