SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1c023b95dd6a4183863dfd51f42200496ac50780303438f1c99d5e52470aa50' 
  AND token = '6IXDMcEBsBrfu3UnnsOTad1TE48hZKzHN5a6KlxT25E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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