SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e64e1d0c3ff9bf05ce582c0aa9af9e49225510483e50322ee7946272480be75' 
  AND token = 'xQ4XW1+dPJohkzgktLIiewg0pOywdijNutv4ftetw1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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