SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c39f722cfbe09571b0968ac481df05457e52f4c88a17c79d26437808861bf97' 
  AND token = '64KV2CvgxSfHzwqWTgqGLGRuDJWoOX04s/a8HT2/UAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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