SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cce9d6138c0822bd754d7828c5309f163f86a05c8db9079f2fcb7e1499a31525' 
  AND token = '8kL7WRjZPTkqZ9rWf4C4KbDh1TUCz0ybEmhypADNnq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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