SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8b7c9d0213a20a965ccd8cd8440deba89be5ed1f13457111b2c94fbe1a8281b' 
  AND token = 'bd5dDb7zsZY34dnXXsTYqsySMQ50X2PVJpvtxXxajL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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