SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1418c2a70bc5fd7694109eb56c5a2287d934ac06b075ba4d5af73ef879e0533' 
  AND token = 'L/xIlhpFQhEdU4Yn8JQvie7ardl3IDOW4EF/WcU4urM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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