SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2da55a41b4c68d64842ae29b88105a3360e4b7a073d194b341252b54aea9e66f' 
  AND token = 'BkqHbYFSsK1J/FQh2/M+DNwzDDWXsu7EHfI6HuXXWBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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