SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93ecec18a9ce10ad1ede9a7b101a2e84e5afa0d9b32cefd7cd81084d2c70bc7c' 
  AND token = 'JNxIWhApp6BIbPwfBOTFUu/ls7QjN0RIKVkjLwX86AM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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