SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfd3f86a88991970e86b566ad78a635b993fcdc0fbd80a58955be40f3f07a41c' 
  AND token = 'ELnzAOXT7yJN5s/3hINXWkFaHaVPwjquJXFdXd349+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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