SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '405e1943e890d036c9a75e792420282da2eaa649daaf657b68ecf2c5c99c03a2' 
  AND token = '5P4qYr/rGDTWQLiVZxxyS0jamZAA2ab+fRvmJU1EUK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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