SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b097c7ce4b21838adab17a8107b06af22f1e8ef9f890e62f05a7e4a21ce8ce6' 
  AND token = 'BZ+Z4NTMArSUpUtBRJceOZnuLIDToGUWr06BAnvgfvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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