SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a84702bb7fb74581d22957ab4242137f0811f4c03af51854ccbd496893fa60be' 
  AND token = '3apo5QW+5prLYdL4dBeLAyD+VN051OpzRpsiR0upWA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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