SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b7828b29b3551a5a1637d403cc19c1a01bdb374b91028540f0d002c380f6dc8' 
  AND token = 'mHaOm9sAMrd3oUCTL+GcOGfglUZNFPN23tMJgKINwXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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